This invention relates in general to mechanical interconnections between mechanical receptacles and substrates with electrical circuits situated thereon. More particularly, the invention involves a keying arrangement for controlling connection of a printed wiring assembly or a similar structure to a specific receptacle in a backplane structure.
In modern electronics, it has become commonplace to interconnect several printed wiring boards or assemblies or printed circuit cards through a common interconnection board or wiring assembly generally referred to as a backplane. Typically each printed wiring board is mounted perpendicular to the backplane within a card rack. For example, contemporary programmable logic controllers employ a backplane having a plurality of parallel female multi-pin DIN or similar type electrical connectors. Each backplane connector is adapted to receive a mating male connector situated on an edge of a respective printed wiring board.
In general, each female connector is uniquely wired or software configured to provide proper circuit interconnection to a specific type of the printed wiring boards (PWB). If the wrong PWB type is inserted into one of the backplane connectors, at best the system may not work and in a worst case may result in significant electrical circuit destruction. For that reason, the DIN connectors are often "keyed" to prevent improper or incompatible connection. However, it is known that such keying of connectors per se has often been ineffective and requires unique keying of individual connectors on replacement PWB's.